Nearby Friends: Facebook's location service will help you meet in the park and target adverts

Smartphones are perfect for location-based services - but most have failed to go mainstream because of privacy worries

Facebook has introduced a new feature named Nearby Friends that allows users to broadcast their location with an accuracy of half a mile.

Facebook has stressed that this service is optional and comes turned off by default, but the social network has also confirmed that users’ Location History will be used to target them with adverts “in the future”.

As well as sharing their location and viewing the location of contacts who are also signed up, Nearby Friends will also allow users to sign-post where they’ll be for a set period of time. Facebook are hoping this will help people find each other in vague locations like parks or airports.

The feature locates individuals by using a combination of GPS data and triangulation from nearby mobile towers; a method which Facebook says drains less battery than rival location apps such as Foursquare.

If users don’t have Nearby Friends turned on then Facebook may slip adverts for the feature into their newsfeed, notifying individuals that “3 friends are nearby” but that they will need to turn the service on to find out who.

The service is opt-in and availble to only-18s only.

The service could be useful for a range of tasks, from finding friends on a night out to keeping tabs on children during a family holiday. It also rebuts criticism of Facebook as a tool that isolates rather than ‘connects’ individuals.

However, users are likely to object to the idea that their physical location might be used to serve them targeted adverts - despite the fact that individuals’ ‘Location History’ will be placed in their Activity Log (the record of all their interactions – likes, photos, etc) where it can be viewed and deleted .

Facebook will be rolling out the service slowly to its 1.23 billion users, with this cautious approach reflecting the company’s realisation that the issue of privacy is still one that can scare away individuals. However, if people are persuaded to turn on the service at some point it won't be of any use to the company - Facebook will have to tread a fine line between encouragement and coercion.